Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 9af814208502a3c1b389f1cb3ba9e53c0caa542d
      
https://github.com/WebKit/WebKit/commit/9af814208502a3c1b389f1cb3ba9e53c0caa542d
  Author: Yijia Huang <[email protected]>
  Date:   2026-03-04 (Wed, 04 Mar 2026)

  Changed paths:
    M Source/JavaScriptCore/bytecode/CodeBlock.cpp
    M Source/JavaScriptCore/bytecode/CodeBlock.h
    M Source/JavaScriptCore/bytecode/UnlinkedCodeBlock.h
    M Source/JavaScriptCore/dfg/DFGJITCode.cpp
    M Source/JavaScriptCore/dfg/DFGToFTLDeferredCompilationCallback.cpp
    M Source/JavaScriptCore/runtime/Options.cpp
    M Source/JavaScriptCore/runtime/Options.h
    M Source/JavaScriptCore/runtime/OptionsList.h

  Log Message:
  -----------
  [JSC] Implement Quick FTL Tier-Up for proven-stable functions
https://bugs.webkit.org/show_bug.cgi?id=309170
rdar://171728162

Reviewed by Dan Hecht, Keith Miller, and Yusuke Suzuki.

This patch extends the Quick DFG Tier-Up mechanism one level higher,
applying the same stability-based acceleration from DFG to FTL.
Functions that have already proven DFG stability (isQuickDFGTierUp())
and successfully installed FTL code are marked as quick FTL tier-up
candidates using a TriState flag on UnlinkedCodeBlock, following the
same state machine as the DFG variant:

- Indeterminate -> True:          didInstallFTLCode() (successful FTL install, 
only if isQuickDFGTierUp())
- Indeterminate -> False:         didFailFTLCompilation() (compilation failed)
- True -> False:                  didFTLJettison() (post-install speculation 
failure)
- Indeterminate -> Indeterminate: didFTLJettison() (environmental issue, no 
penalty)

For functions marked as quick FTL tier-up, DFGJITCode::optimizeAfterWarmUp
applies quickFTLTierUpThresholdFactor to reduce the DFG-to-FTL compilation
threshold. Note that only macOS is currently configured to use quick FTL 
tier-up.

Canonical link: https://commits.webkit.org/308663@main



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